How to build outdoor kitchen with a concrete benchtop?

[maccifo]

A few years ago, I decided to do an outdoor kitchen (under a pergola) which has been very useful and practical. However, I didn't feel confortable building a concrete slab and instead I used marine plywood with tiles (I am still regretting this decision). So if you are reading this post because you are unsure ... don't install tiles! They have been very practical but the look it is not the best and won't add much value to your house if you are thinking on selling it later on.

Therefore, I have decided to remove it (including the side panel), install an extra kaboodle cabinet (400mm) and install a proper concrete slab. See picture below:

The dimensions will be around 1900mm x 750mm x 30mm (and 1080mm for the heigh of the side slab). I am planning to use:

• CUSTOMpine 16 x 2400 x 1200mm White Matt Carcass Particleboard MR - Bunnings Australia
• MaxPRO 20kg Concrete Mix - Bunnings Australia
• Jack 600mm x 5m Reinforcing Mesh Roll - Bunnings Australia
• WD-40 300g Specialist High Performance Silicone - Bunnings Australia

I have the following questions:

• Is 30mm enough? I don't want to do less because the top i am replacing is already 30mm so i don't want to paint the wall again (with thinner top)
• Is the reinforcing mesh roll enough with the Fibre reinforcement concrete mix?
• I am thinking on pouring it on a table and then moving it (around 100kg) to the final position. Any other ideas?
• For the side slab (side panel), is it enough if it is glued to the side cabinet? Otherwise, is there any other recommendation to fix it?

Thanks for your help. I can't wait to start this project.

[JacobZ]

Hi @maccifo,

Thank you for your question about creating a concrete benchtop for your outdoor kitchen.

There isn't a huge amount of information about standards when it comes to these concrete benchtops, so I can't point you to anything giving a definitive answer as to whether this is thick enough. In saying this, most of my research has said that a concrete benchtop is usually around 30-50mm thick, with fibre reinforced concrete and steel reinforcing advised for those thinner benchtops. I am fairly confident that 30mm should be fine as long as you ensure the reinforcing is fully encapsulated and doesn't poke out anywhere.

I think pouring it elsewhere and then moving it into place is likely the way to go. This will allow you to have free movement all around the slab so it can be easily worked on.

I'd be much more comfortable if the benchtop and side panel were both glued, using an adhesive such as Liquid Nails Landscape Adhesive, as well as held with mechanical fixings. You might be able to put 25mm Green Wall Plugs in place while pouring the slabs, then use angle brackets and screws to fix them in place alongside the glue. Setting the wall plugs in place while pouring would remove much of the risk of damage that would happen if you needed to drill into the concrete after hardening to install them, so if this could be done, it would certainly be worthwhile.

Allow me to tag @Wadsy1, whose Concrete countertop outdoor kitchen is very similar to what you are trying to achieve. You might get some inspiration from their project and maybe they can offer you some advice or insight.

Let me know what you think.

Jacob

[maccifo]

Thanks for the advise. This project didn't go ahead I am afraid...

[EricL]

Hello @maccifo 

I propose practicing by building small paving steps in formwork. You'll be able to see the process and feel how concrete works. This practice will also reveal things you need to watch out for such as levelling cement and removing trapped air bubbles in concrete. 

I also recommend having a look at this discussion - Concrete tabletop project by @markw. It is an excellent example of how you can build a solid concrete tabletop.

If you need further assistance, please let us know. 

Eric